Shoe sewing machine



Oct. 3, 1939.

o. R* HAAs 2,175,056

SHOE SEWING MACHINE Original Filed April 29, 1956 6 Sheets-Sheet 1 wi M:

Snventot Oct. 3, 1939; o. R. HAAS 2,175,056

SHOE SEWING MACHINE Original Filed April 29, 1956 6 Sheets-.Sheet 2 3 nnentor Oct. 3, 1939. o. R. HAAs SHOE SEWING MACHINE original Filed April. 29, 193'6 6 Sheets-Sheet 3 Snventor Oct. 3, 1939. o. R. HAAs SHOE SEWING MACHINE 6 Sheets-Sheet 4 Original Filed April 29, 1936 Snventor Oct. 3, 1939. O. R. HAAs 2,175,056

sHoE sEwiNG MACHINE Original Filed April 29, 1936 6 Sheets-Sheet 5 Z6 A May/mmm? i oct. 3, 1939.l

O R. HAAS SHOE SEWING MACHINE Original Filed April 29, 1936 6 Sheets-Sheet 6 Envenfor Patented Oct. 3, 1939 UNITED STATES PATENT OFFICE SHOE SEWING MACHINE Original application April 29, 1936, Serial No. 76,924. Divided and this application April 6, 1938, Serial No. 200,411

Claims.

The present invention relates to sewing machines, and more particularly tc improvements in presser foot mechanism for machines in which the work is alternately clamped and released by the presser foot during each stitch forming cycle of the machine.

The invention is particularly adapted for use in sewing machines employed in the manufacture of shoes to sew the outsole to welted uppers, and is illustrated as embodied in a machine of that type, the particular machine being more fully described and shown in the present inventors pending application Serial No. 76,924, of which the present application is a division. The invention is, however, well adapted for use in sewing machines of other types and modes of operation.

The present invention has for its object the provision for use in sewing machines, of presser foot actuating and locking mechanism of novel and improved construction and arrangement, whereby the work may be effectively clamped and released at the proper times in the stitch forming cycle of operation, even when the machine is operated at high speeds.

With the above and other objects inview, a feature of the invention consists in the provision of work clamping mechanism comprising a presser foot lever, the actuating connections of which are arranged to act along a line passingbetween the work engaging surface of the presser foot and the fulcrum of the presser foot lever'and closely adjacent the work engaging surface of the presser foot, whereby there will be no tendency of the presser foot to move after being locked, even though there may be looseness in the fulcrum or elsewhere in the mechanism.

Another feature of the invention consists in the provision of presser foot mechanism comprising a Wedge block connected to the presser foot, a locking wedge block arranged to engage and lock the presser foot in clamped position, means for moving the locking wedge block to unlocking position, and connections between the locking wedge block and the presser foot wedge block for raising the 45 presser foot from the work during the unlocking movement of the locking wedge block without the use of springs or other yielding connections.

Still another feature of the invention involves the provision in a sewing machine adapted to feed the work while the work is clamped, of mechanism for moving the presser foot in the line of feed, presser foot locking devices, and a link connecting the presser foot and the locking devices arranged to increase the pressure of the presser foot on the work as the presser foot is advanced to feed the work, and thereby insure that the Work is firmly held against displacement while the work is being fed.

In the drawings illustrating the invention, Figure 1 is a view in right side elevation, partly in section, of the head portion of a shoe sewing machine embodying the invention; Figure 2 is a sectional planview of a portion of the sewing head, showing the mechanism for actuating the feed carriage on which the presser foot is mounted; Figure 3 is a view in left side sectional elevation of a portion of the head of the machine, and further illustrating the work feeding mechanism; Figure 4 is a right hand sectional view of the presser foot actuating mechanism, with the presser foot in work-clamping position; Figure 5 is a view of the presser foot actuating mechanism, shown in Figure 4, as viewed from the left hand side; Figure 6 is a detail View of the presser foot actuating mechanism showing the presser foot in work-clamping position; and Figure 7 is a similar detail View, showing `the presser foot lifted from the work.

'Ihe head portion of the sewing machine eminventors United States Patent No. 2,078,942

dated May 4, 1937.

The stitch forming and work feeding devices of the machine include a curved hook needle I4, a curved awl I6, a needle guide I8, a shuttle or loop taker 20 within a guideway of which is mounted a thread case 22, a looper 24, a thread finger 25, main and auxiliary take-ups 28 and 30, a presser foot 32 andy a worksupport 34. The work is fed continuously by alternating feeding movements of the presser foot and work support as a unit while the work is clamped, and of the needle as a unit when the same engages the work and while the presser-foot is raised.

The presser-footl 32 is locked in gripping engagement with the surface of the work by yielding means acting through an arrangement of locking wedge blocks similar to that described in the United States Patent to Ashworth No. 1,756,502 of April 29, 1930. In the machine of that patent as well as in inventors Patent No. 2,031,479 the connection between the presser-foot lever and the locking wedge blocks is at the rearward side of the fulcrum of the presser-foot lever opposite the work engaging surface of the presser-foot and beneath the presser-foot lever.

To improve the operation of the presser-foot actuating connections of the present machine, the presser-foot locking wedge blocks are mounted above the presser-foot 32 and a single link 40 (see Figs. 1, 6 and '7) is pivotally connected between one of the wedge blocks and a lever 42 upon which the presser foot is mounted. The fulcrum for the presser-foot lever 42 comprises a horizontal shaft 44 at the rearward end of the lever. The link 40 is so connected to the presser-foot lever that it acts under compression along a line passing between the work engaging surface of the presser-foot and the axis of the fulcrum shaft 44 as close as possible to the work engaging surface of the presser foot. With the connections arranged in this manner, if there is any looseness in the fulcrum of the presser-foot lever or else- Where, there will be no tendency of the presser foot, after being locked, to move as a result of this looseness. As an additional precaution, the upper end of the link 40 is somewhat to' the left of the lower end thereof, as shown in Fig. 6, so that during feeding movement of the presserfoot towards the left, the grip on the work will be tightened as the link becomes more nearly vertical.

The presser-foot link 40 is connected at its upper end to a wedge block 46 mounted to slide in a Wedge boX 48 secured in the machine frame with one of its wedging .surfaces in contact with an inclined surface on the wedge box. To force the presser-foot wedge block 46 downwardly, it is engaged along its other wedging surface by a locking wedge block 50 also mounted within the wedge box 4B. Formed integrally with the locking wedge block 50 is an upwardly extending rod portion 52, the upper end of which carries apin 54. Pivoted on the opposite endsof the pin 54 at either side of the rod 52 is a pair of links 56, the lower` ends of which are pivotally connected to the ends of a forked arm 58V of arlever 60. The lever 60 is rotatably mounted on a shaft 62 and has an upstanding arm 64 connected with one end of a tension spring 66, the other end of which is connected with a lug 68 formed on the frame of the wedge box 48. The spring 66 acts to force the locking wedge block 5l)l against the. presserfoot wedge block 46, thus imparting a downward pressure of the presser-foot against the'work.

To raise the presser-foot intermittently from the work during sewing, the rod portion of the locking wedge block 50 is surrounded at its central part by a yoke 10 (see Figs. 4 and 5) between the lugs of which a gripping arm 12 is pivotally mounted. 'Ihe yoke 10 is normally held in lowered position by a spring 14 surrounding the rod portion 52 of the locking wedge block between-the yoke 10 and a bearing 16 at the top of the wedge box 48. The gripping arm 12 is forked atits rearward end and surrounds a squared block 'I8 pivoted between the-parallel arms of a lifting lever 80 also fulcrumed on the shaft 62. The lever 80 has a slotted arm in which is adjustably secured the pivot 82 for one'end of a link 84 (see Fig. 1), the other end of which is connected to a cam actuated lever 86 fulcrumed on a horizontal shaft 88. When thelever 86 is actuated, the camshaped forward end of arm 12 acts directly against the locking wedge block rod 52 to raise the locking wedge block a predetermined distance during each cycle of operations of the machine.

The lever 86 then lowers the gripping arm until the yoke 10 strikes a right angle plate 90 adjustably secured to the wedge box 48 by a threaded stud 9|, Further downward movement of the lever 86 then causes the grip of arm '|2 to be released so that the spring 66 may again move the presser-foot yieldingly against the work, as shown in Fig. 6.

To cause the presser-foot wedge block 46 to be raised to the position of Fig. '7 with the locking wedge block 50, there is provided a train of connections between the locking wedge block and the presser-foot block 46, separate from the connections for actuating the locking wedge block. These connections comprise a lever 92 pivotally connected at its right end with the locking wedge block 50, intermediate its ends with a link 94, and at its left end with a link 96. 'I'he link 94 is connected with the presser-foot Wedge block 46 and the link 96 with the stationary locking wedge box 48. The link 96 is formed with an enlarged opening 98 through which a stud |00 threaded into the frame of the wedge box passes, .so that a small amount of lost motion will be permitted in the connections. otally connected to the lever 92 at such point intermediate the ends of the lever that the presser-foot block is caused to travel at the same rate of movement relatively to the movement of the locking wedge block in retracting the presserfoot from the work as when moved by the wedging surface of the locking block in forcing the presser-foot against the work. Since the movement imparted by the locking wedge block to the presser-foot block in clamping the work is slower than the movement of the locking wedge block, the corresponding movement produced by the link and lever connections thus described, causes the presser-foot block to move more slowly than the locking wedge block during retraction of the presser foot from the work. By so connecting the wedge blocks the locking block may be actuatedV directly by the actuating mechanisms, and no springs or other yielding connections are required to lift the presser-foot from the work during sewing.

The mechanism for raising the presser-foot at the end of the seam comprises a lever |02 pivotally mounted on shaft 62 and having a horizontal arm |03 which underlies a set screw |04 carried by the lever 60. An upstanding arm |05 of the lever |02 is connected to the forward end of a link |06, the rearward end of which is pivotally connectedwith a lever |08 actuated by a cam I0 rotatable on a shaft ||2 at the rear of the sewing shaft |2. The cam ||0 is connected with a onerevolution clutch of the same construction and mode of operation as described in the present inventors Patent No. 2,078,942 above referred to. The clutch is brought into operation when-ever the driving and stopping mechanism is actuated to stop the machine during thenal movements of the sewing shaft I2.

To maintain the presser-foot in raised position, the lifting lever 60 is formed with a suitably shaped lug ||4, and a latch ||6 (see Figs. 4. and 5) mounted in a lever ||8 fulcrumed on the shaft 88, is disposed directly above th-e lug. When the presser-foot is raised, the forward end of the latch lever ||8 is raised against the force of a spring-pressed plunger |20 (Fig. l) slidably mounted in the lever and disposed to engage the under surface of a portion of the machine frame. The latching end of the lever |I8 then moves in The link 94 is pivfront of the lug to hold the lever 60 in raised position.

To release the presser-foot and permit it to engage the work when the treadle is depressed, the rearward end of the latching lever |8 is connected to a link |22 by means of a pin |24 carried by the lever and passing through the slotted upper end of the link |22. The lower end of the link is connected to an arm |26 clamped to a sleeve |28 rotatable in the machine frame. By connections between the sleeve |28 and the treadle rod of the machine, which connections are fully illustrated and described in Patent No. 2,078,942 above referred to, the sleeve is rocked upon depressing the treadle to start the machine to swing the latching lever ||8 in a direction to lift the latch ||6 out of engagement with lug ||4 and thereby release the presser-foot.

The presser foot and work support are mounted on a laterally sliding carriage |30 to permit them to be moved in the line of feed. The feed carriage is provided with horizontal gudgeons |32 extending in opposite directions 'from the carriage |30 near the central part of the carriage and supported for sliding movement in circular guideways in the machine frame. To prevent rotation of the carriage about the gudgeons there is pivotally connected at the rear of the carriage the upper end of a vertical link |34 (see Fig. l), the lower end of which is pivotally mounted on the machine frame. The link |34, extending substantially at right angles to the line of feed, causes but a slight vertical movement in the feed carriage.

To move the feed carriage in the line of feed, the gudgeon |32 at the left of the carriage is connected to one arm of a suitably actuated lever |36, said arm being formed at its end with two vertical separated forked portions, between the ends of which are slidable a pair of blocks |38. The blocks |38 are pivotally mounted upon a vertical pin |40 secured within the end of the gudgeon |32 (Fig. 3). The lever |36 is mounted on a vertical shaft |42 in the frame and is provided with a laterally extending arm pivotally connected by a link |44 with a lever |46. The lever |46 is supported on a horizontal shaft |48 carried by the machine frame and the lever is formed with an elongated hub carrying a pair of arms |50 pivotally connected one at each side to an open oscillating frame |52. The frame |52 carries a cam roll |54 cooperating with a cam on the sewing cam shaft and is pivotally connected by means of a pin |56 with the lower end of a link |58, the upper end of which is rotatably mounted on a stud |60 secured in the end of one arm of a yoke member |62. When the sewing shaft is rotated the frame |52 is rocked about the shaft |48 and stud |60 as centers, the arms |50 and link |58 acting as guides for the movement of the frame. The link |58 and that portion of frame |52 between pin |56 and the pivotal connection of arms |50 comprise a pair of toggle members for driving the feed slide, the relative position of stud |60 determining the amount of movement imparted to the feed slide.

Having thus described the invention, what is claimed is:

1. A sewing machine having, in combination, stitch forming devices, a Work support, a presser foot and presser foot actuating mechanism including a wedge block operatively connected to the presser foot, a locking wedge block arranged to engage the presser foot Wedge block to lock the presser foot against movement away from the work support, spring meansfor forcing the locking,block yieldingly against the presser foot block to apply thef presser foot to the work, unlocking' means acting on the locking wedge block to move it against the force of the spring means, and connections between the wedge blocks separate from the unlocking means for moving the presser foot block with the locking wedge block to retract the presser foot from the work support.

2. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot and presser foot actuating mechanism including a wedge block operatively connected to the presser foot, a locking wedge block arranged to 'engage the presser foot wedge block to lock the presser foot against movement away from the work support, said locking block being arranged when moved against the presser foot block to impart movement at a slower rate to the presser foot block, spring means for forcing the locking block yieldingly against the presser foot block to apply the presser foot to the work, unlocking means connected to the locking wedge block to move it against the force of the spring means, and connections between the blocks separate from the unlocking means for moving the presser foot block to raise the presser foot from the work at the same rate relatively to the movement of the locking block as when applying the presser foot to the work.

3. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot and presser foot actuating mechanism including a wedge block operatively connected to the presser foot, a locking wedge block arranged to engage the presser foot wedge block to lock the presser foot against movement away from the work support, spring means for forcing the locking block against the presser foot block to apply the presser foot to the work, and means for unlocking the presser foot including a member actuated during each cycle of stitching operations to grip a portion of the locking block and move the block against the force of the spring means and connections between the wedge blocks, separate from the means for moving the looking wedge block, for moving the presser foot block with the locking block to raise the presser foot from the work.

4. A sewing machine having, in combination stitch forming devices, a work support, a presser foot, a presser foot lever, a fulcrum for said lever, and presser foot actuating mechanism including locking devices, spring means for forcing the locking devices in a direction to move the presser foot towards the work support and to lock the presser foot from separation from the work support, and a connection from the locking devices to the presser foot lever arranged to act on the presser foot lever along a line passing between the work engaging surface of the presser foot and the fulcrum of the presser foo-t lever.

5. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot, a presser foot lever, a fulcrum for said lever, and presser foot actuating mechanism including locking devices, spring means for forcing the locking devices in a direction to move the presser foot towards the work support and to lock the presser foot from separation from the work support and a link connecting the locking devices and the presser foot lever arranged with its lengthwise axis directed along a line passing between the Work engaging surface of the presser' foot andthe fulcrum tof the lpresser foot lever. Q

6. A lockstitch' sewing machine having, -in combination, stitch forming devices including a loop taker, a locking thread case and a curved hook needle, a work table arranged to` support the work against the thrust of the needle, a presser foot for clamping the Work against the work support, a presser foot lever, 'a fulcrum for said lever, andv presser foot actuating mechanism including devices at the presser foot vside of the work for locking the presser foot against the work, spring means for moving the presser foot towards the work support, and a link connecting the locking devices and the presser foot lever arranged to act under compression in holding the presser foot against the work.

7. A lockstitch sewing machine having, in combination, stitch forming devices including a loop taker, a locking thread case and a curved hook needle, a work table arranged to support the work against the thrust of the needle, a presser foot for clamping the work against the work support, a presser foot lever, a fulcrum for said lever, and presser foot actuating mechanism including devices at the presser foot side of the work for locking the presser foot against the work, spring means for moving the presser foot towards the work support, a link connecting the locking devices and the presser foot lever arranged to act under compression in holding the presser foot against the work, and connections for actuating the locking devices to unlock and raise the presser foot from the work.

8. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot and presser foot actuating mechanism including a wedge block operatively connected to the presser foot, a locking wedge block arranged to engage the presser foot wedge block to lock the presser foot against movement away from the work supportythe cooperating surfaces of said blocksvr being arranged when the locking block is moved against the presser foot block to cause the presser foot block to travel at a slower rate than the locking block, and connections between the blocks for causing the presser foot block to travel at the same rate relatively to the movement of the locking block in retracting the presser foot from the work support.

9. A sewing machine having, in combination, stitch forming. devices, a work support, a presser foot, a presser foot lever, a fulcrum for said lever, and presser foot actuating mechanism including a wedge block, a link connecting the wedge block and the presser foot lever arranged with its lengthwise axis directed along a line passing between the work engaging surface of the presser foot and the fulcrum of the presser foot lever, and a locking wedge block aranged to engage the first mentioned wedge block to lock the presser foot against movement away fro-m the work support.

l0. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot, presser foot'actuating mechanism including locking devices, mechanism for moving the presser foot in the line of feed to feed the work and a link connecting the presser foot and the locking devices arranged to increase the pressure of the presser foot on the work as the presser foot is moved to feed the work.

OTTO R. HAAS. 

